Nowadays, many fresh water supplies are polluted. Consumers usually obtain their drinking water from bottle water or water vending machines. Such water is usually purified by various kinds of purification equipment such as the reverse osmosis system. The most common filters nowadays are the reverse osmosis filter and ion exchange resin filter. Many households even have their own reverse osmosis or ion exchange resin units installed at home. However, all purification equipment must be efficiently maintained by replacing their filters after a certain period of time suggested by the manufactures.
Actually, the service life of filter depends on the quantity of water being purified. The more quantity of water flows through the filter, the quicker the filter loses its purifying ability. In fact, the filter of a purification equipment would be replaced while it is still normally functioned if the user maintains the purification equipment merely depending on its operating time. On the contrary, the filter of a purification equipment may lose its purifying function before the maintenance due date suggested by the manufacturer if a large quantity of water is purified within a short period of time. Thus, the user of the purification system may still has a great chance of drinking dirty and unsanitary water which is much dirtier than the tap water since the malfunctioned filter will become a breeding ground of bacteria and germ.
Accordingly, in order to maintain a purification equipment economically and effectively, the correct method of maintaining a purification system is to compute its quantity of purified water, i.e. the quantity of water flowing through the filter. After a certain quantity of water is purifying by the filters of a purification system, the filters may lose their purified ability and need to be replaced. A measuring device for recording the accumulative quantity of water that has passed through the purification system is therefore in demand to ensure a good purifying quality of the equipment.
A flowmeter of prior technology is made of mechanical coaxial sets of gears of different sizes that are moved by the water flow. Such mechanical device bears the disadvantages of inaccuracy due to the limitation of mechanical structure and the required large overall size of the device that makes it difficult to install on the purification system.